• RX Format: label BCT R,D(X,B)

• Decrements the value in R by 1 and branches to D(X,B) if the value in R is not 0

• If R contains 0, instruction immediately following BCT is executed

• RR Format: label BCTR R₁,R₂

• Decrements the value in R₁ by 1 and branches to the address in R₂ if the value in R₁ is not 0

• If R₁ contains 0, instruction immediately following BCTR is executed

• EXCEPTION: If R₂ is register 0, then 1 is subtracted from the value in R₁ and NO branch is taken

       LA    R4,3              LA    R4,3              LA    R4,3
DO1    LTR   R4,R4      DO1    LTR   R4,R4       DO1   XREAD BUFFER,80
       BZ    ENDDO1            BZ    ENDDO1            XPRNT BUFFER,80
       XREAD BUFFER,80         XREAD BUFFER,80         BCT   R4,DO1
       XPRNT BUFFER,80         XPRNT BUFFER,80   EXIT  BR    R14
       S     R4,=F‘1’          BCTR  R4,R0
       B     DO1               B     DO1
ENDDO1 DS    0H         ENDDO1 DS    0H
EXIT   BR    R14        EXIT   BR    R14